package com.jfl.utils;

import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * Ajax工具类
 * 
 * @author 赵炎
 * @version [V1.00, 2018年12月9日]
 * @since V1.00
 */
public class AjaxUtil
{
    /**
     * 是否是Ajax异步请求
     * 
     * @param request
     */
    public static boolean isAjaxRequest(HttpServletRequest request)
    {
        
        String accept = request.getHeader("accept");
        if (accept != null && accept.indexOf("application/json") != -1)
        {
            return true;
        }
        
        String xRequestedWith = request.getHeader("X-Requested-With");
        if (xRequestedWith != null && xRequestedWith.indexOf("XMLHttpRequest") != -1)
        {
            return true;
        }
        
        return false;
    }
    
    /**
     * 将字符串渲染到客户端
     * 
     * @param response
     *            渲染对象
     * @param string
     *            待渲染的字符串
     * @return null
     */
    public static String renderString(HttpServletResponse response, String string)
    {
        try
        {
            response.setContentType("application/json");
            response.setCharacterEncoding("utf-8");
            response.getWriter().print(string);
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
        return null;
    }
}
